Line-orientation generalization following signalled-reinforcer training

Three naive and three nonnaive pigeons key pecked for food on a multiple variable-interval 1-minute variable-interval 1-minute schedule with a black zero-degree vertical line on a white surround associated with one component and a black line shifted 30 degrees to the right (+30 degree) associated with the other component. Subsequently, a signalled-reinforcer procedure was introduced in the +30 degree component, i.e., whenever the reinforcer was available for the next response, the key changed to blank white. Following this training, the original unsignalled-reinforcer condition was re-instated. Line orientation generalization tests were given at the end of signalled-reinforcer training and after the second unsignalled-reinforcer condition. The signalled-reinforcer procedure reduced response rate in the +30-degree component in all subjects but facilitated responding during the zero-degree component (behavioral contrast) for two of the naive subjects only. However, average generalization gradients following signalled-reinforcer training indicated peak shift in two subjects and area shift in all five subjects that completed the experiment. There was no apparent relation between contrast and peak shift or degree of area shift. The data were interpreted as supporting the notion that the signalled-reinforcer procedure segments a variable-interval schedule into extinction and fixed ratio 1 segments.     

Generalization gradients following two-response discrimination training

Stimulus generalization was investigated using institutionalized human retardates as subjects. A baseline was established in which two values along the stimulus dimension of auditory frequency differentially controlled responding on two bars. The insertion of the test probes disrupted the control established to the two S^Ds during training. The discrimination was recovered between each test probe and the resulting gradients were stable across 10 test sessions. These gradients, supported by other two-response generalization studies, indicate that this type of two-response discrimination training divides the stimulus dimension into two functional classes separated by a region of transition from one class to the other. Each stimulus value in a class, which extends from an S^D outward to the functional limit of the dimension, controls a similar proportion of the two responses as each other value in the class. All values on the stimulus dimension control identical response rates with an absence of the usual generalization decrement. The latency of the initial response, however, shows a bimodal gradient with the modes at the S^D values.     

Additive summation following intradimensional discrimination training

Rats were exposed to intradimensional composite stimuli presented on the response lever that varied in both light intensity and flicker rate. For all subjects, pressing the lever was reinforced when it was illuminated at a high intensity and flickered at a low rate (I + f) or when it was illuminated at a low intensity and flickered at a high rate (i + F). For half the subjects, lever responding was not reinforced when it was illuminated at a low intensity and flickering at a low rate (i + f). For the remaining subjects, lever presses were not reinforced when the lever was illuminated at a high intensity and flickered at a high rate (I + F). When the composite stimulus composed of the light intensity and flicker rates that had been associated only with reinforced responding was displayed (I + F for half the subjects and i + f for the remaining subjects), it controlled the highest response rate of all stimuli (additive summation). The results demonstrated that similar attentional processes control intra- and interdimensional composite-stimulus discriminations in a manner consistent with Weiss' (1972) analysis of summation.     

Attentional demands following perceptual skill training

Practicing simple visual tasks induces substantial improvement. We investigated whether increased efficiency is accompanied by automaticity and immunity to across-task interference. We found that although practice speeds orientation feature detection, it does not abolish susceptibility to interference from introduction of concurrent central-letter identification, which takes priority. Yet following training with each task, observers successfully managed to perform the tasks concurrently. The effectiveness of separate training implies that the role of improved intertask coordination in achieving concurrent performance was minor. Indeed, even when initial training was concurrent, improvement on the two tasks was sequential, and the higher-priority (central) task was learned first. However, automatic processing was not accomplished either, because increasing the difficulty of the higher-priority task interfered with performance of both tasks. What appears to be orchestrated posttraining performance is actually mainly an emergent property of speeded initial processes rather than either eliminated bottlenecks or improved central executive management.     

Improved classification of mammograms following idealized training

People often make decisions by stochastically retrieving a small set of relevant memories. This limited retrieval implies that human performance can be improved by training on idealized category distributions (Giguère & Love, 2013). Here, we evaluate whether the benefits of idealized training extend to categorization of real-world stimuli, namely classifying mammograms as normal or tumorous. Participants in the idealized condition were trained exclusively on items that, according to a norming study, were relatively unambiguous. Participants in the actual condition were trained on a representative range of items. Despite being exclusively trained on easy items, idealized-condition participants were more accurate than those in the actual condition when tested on a range of item types. However, idealized participants experienced difficulties when test items were very dissimilar from training cases. The benefits of idealization, attributable to reducing noise arising from cognitive limitations in memory retrieval, suggest ways to improve real-world decision making.     

Dimensional stimulus control following brief wavelength training

Pigeons with extensive training pecking a key illuminated by a white line then had brief training with the key illuminated by 555 nanometers. This was immediately followed by a wavelength generalization test in extinction. Dimensional stimulus control about the training wavelength increased with the duration and number of reinforcements given on variable-interval 30-sec and variable-interval 10-sec schedules in Experiment I. In Experiment II, dimensional stimulus control was obtained after only 4 min of wavelength training from birds with prior and independent discrimination training. Experiment III provided groups equated in number of reinforcers with groups in Experiment I and two 8-min duration groups. Analyses, which included results from both Experiments I and III, showed that dimensional stimulus control increased: (a) more rapidly as a function of the duration of variable-interval 10-sec than variable-interval 30-sec reinforcement; (b) at the same rate across variable-interval reinforcement schedules, as a function of the number of reinforcers available during brief wavelength training.     

Psychosocial issues following traumatic brain injury

The author contends that Dean, Colantonio, Ratcliff, and Chase in 2000 probably underestimated the importance of psychosocial factors in the very long-term adaptation to disability by 166 individuals with traumatic brain injury.     

Physical training and personality factors as predictors of marathon time and training injury

On the basis of surveys completed by 105 male participants in a popular marathon, a multiple regression analysis was conducted to identify the variables contributing significantly to the prediction of final time. Overall prediction was successful, with R = .896, and training pace was the most important factor in the equation, speedier workouts being associated with faster marathon times. Final time was also related positively to best 10-km race time in the previous 12 mo. and repression-sensitization (faster runners being more sensitized), and negatively to maximum number of training miles in a single week, number of previous marathons completed, and number of days of training lost through illness or injury. Contrary to expectations, locus of control was not related to final time. Only 27% of the runners had lost training time through injury, but a discriminant analysis showed that, compared to those who had avoided this problem, the injured were younger, rested less, ran less in the week prior to the marathon, ran a slightly longer long run but ran it earlier before the race, and ran fewer runs of 20 miles or more. It is suggested that researchers should study the repression-sensitization variable and investigate injury in runners preparing for a marathon.     

Self-instruction: An analysis of the differential effects of instruction and reinforcement

This study investigated the impact of training 9 first- and second-grade children to use a full self-instructional regimen, and then differentially reinforced the use of self-instruction only, accuracy only, or both self-instruction and accuracy. Three comparison children received no training in self-instruction and were reinforced for accuracy only. Children improved dramatically in academic accuracy subsequent to self-instructional training, independent of the use of self-instruction and of the specific behavior consequated. Children who were reinforced for using self-instruction did use self-instruction, and those who were not, did not. Comparison group children showed little improvement until training in problem-solving strategies was given after 9 days of reinforcement for accuracy. Self-instructional training is discussed as one type of event that increases the likelihood of accurate performance. Its effectiveness may be explained in terms of a teaching strategy rather than in terms of modifying cognitive processes.     

Contrast and stimulus generalization following prolonged discrimination training

Different groups of pigeons received discrimination training in which the reinforcement-associated and extinction-associated stimuli were respectively either (a) a line tilt vs a blank key, (b) a blank key vs a line tilt, or (c) two different line tilts. The high response rates that developed to the positive stimulus in all groups during discrimination learning were maintained over 64 sessions of training. After these sessions, all subjects were tested for stimulus generalization along the line-tilt dimension. Gradients of relative (per cent) generalization around the stimulus associated with reinforcement (so-called excitatory gradients) and around the stimulus associated with extinction (so-called inhibitory gradients) were as steep as they typically are after much briefer training periods. These results do not support several of Terrace's predictions on the basis of the hypothesis that emotional responses develop to the stimulus associated with extinction during discrimination learning with errors, but eventually dissipate after extended training.     

Inhibitory control differences following mild head injury

Complex inhibitory control, defined as the ability to inhibit a planned or ongoing action, was assessed in a sample of individuals with a history of mild head injury, case-matched with normal control subjects for age and gender. This central act of control was assessed using a modification of the stop-signal paradigm. The group with mild head injury took longer to inhibit their on going action and reported more accidents than the normal control subjects. The group that reported having had a mild head injury did not differ in terms of their go reaction time, number of correct responses, handedness, education level, or reported learning disabilities. Limitations of this design and directions for future research are discussed.     

Reaction time unchanged in older women following aerobic training

The effect of aerobic exercise on reaction time in older women was investigated. 14 women (M age = 65 yr.) were carefully screened for health status and lifestyle, then assigned to a random order of the exercise and control groups (ns = 7). Pre- and posttraining tests of aerobic capacity, simple reaction time, and choice reaction time were administered. The exercise group rode a stationary bicycle ergometer for 8 consecutive weeks for 3 35- to 40-min. sessions per week. There were no significant pretraining differences between groups on simple reaction time, choice reaction time, or estimated VO2max. No posttraining differences for simple and choice reaction time were found even though the exercise group had a significantly higher VO2max than the controls. Contrary to some other findings, the data indicate that reaction time may be independent of aerobic training in healthy older women.     

Temporal and spatial control following bilateral versus unilateral training

Principles of motor control and learning such as bilateral coordination and task-specificity, are increasingly incorporated in the design of upper extremity rehabilitation protocols for stroke survivors. Yet most studies investigating the efficacy of new protocols report composite scores of standardized tests, such as the Fugl-Meyer Upper Extremity test (FM) and the Wolf Motor Arm Test, rather than determining how the motor control and coordination of arm movements has changed. Here we present a sub-study of a larger randomized controlled trial comparing a bilateral and unilateral training protocol where participants were assessed on bilateral and unilateral arm reaching. Eligible participants for the arm reaching analysis were 9 (FM=37) and 9 (FM=34) in Bilateral Arm Training with Rhythmic Auditory Cueing (BATRAC) and Dose Matched Therapeutic Exercises (DMTE), respectively. Participants undertook 18 sessions of training for 6 weeks with 20min of active training per session. For bilateral arm reaching, participants after BATRAC were faster, with increased peak acceleration, fewer movement units, and smoother hand paths for each arm. The BATRAC training group showed greater improvements with training than the DMTE group during bilateral reaching for parameters of movement units and smoothness of hand path. For unilateral arm reaching, participants were faster after DMTE for paretic arm reaching; however, this group did not improve to a greater extent than the BATRAC training group. Within group functional gains were seen after BATRAC on FM, Wolf Motor Arm Test (time and weight) and after DMTE on FM and Wolf Weight. There was a positive correlation between movement units and the time component of the Wolf Motor Arm Test. The reaching analysis demonstrates task-specificity in training since BATRAC improves performance in bilateral reaching and DMTE improves performance in unilateral reaching. Temporal/spatial control outcomes in studies of post-stroke interventions can identify functionally relevant motor control changes that are not captured by traditional standardized tests.     

Factors associated with maintenance and relapse following self-management training

In this study, we examined factors associated with relapse and maintenance following a self-management training course. Thirty-five community professionals participated in a 3-week (30-hr) graduate-level extension course in self-management, which included a self-modification project. Results at a 10-week follow-up showed that end-of-class self-efficacy and outcome expectancy correctly classified over 80% of those who maintained gains in their projects versus those who relapsed. The professionals in the relapsed group also reported significantly more difficulty with anticipated high-risk situations than did those in the maintenance group.